Gyratory ore-mill.



G. H. BRADFORD. GYRATORY ORE MILL.

APPLICATION FILED 001 .4, 1911.

Patented Aug. 20, 1912.

GEORGE n. BRADFORD, or BERKELEY, camromiia eYRAroRY ORE-MILK To all wh'oin it may concern:

Be it known that I, GEORGE Berkeley, in the county of Alameda and State of California, have invented new and useful Improvements in Gyratory Ore-Mills, of which the following is a specification.

The presentinvention relates to improvements in gyratory ore mills, the object of verticalintervals with apertures 5, 6, and 7,. so that by suitably closing said apertures,

8, the degree of fine-l by means of shutters ness to which the ore is to be pulverized may be regulated'as desired. Thus, if the lowermost aperture 5- is opened, 50' that the level of the water in the mill stands'only at said aperture, the material will be mesh. If the aperture 6 is closed, and the uppermost aperture 7 opened, then the material will be pulverized to about 150 mesh. And if this aperture be closed, so that the water can escape only over the top of the wall 4, then the material will be pulverized still finer.

Supported upon the base 1 centrally with circular die 9 formed a circular trough 10,

in the wall thereof a near its margin with its central part therein a staple 12 for convenience in dling the same. Between said-die-and the wall of the mortar or base is a ring 13, hav thereof a trough l t" Specification of Letters Patent. Application tiled October 4, 1911. Serial No. 652,694.

I H. BRAhroRD, a citizen of the United States, residing at from which the amaland which will be pulverized to about 0 mesh. If the lowermost aperture 5'. be closed, and the next aperture 6 -opened,; the material will be pulverized to about 80- ;laborious and tedious operation.

improvement, the

1 'ithe pulverized in the trough, I 'saidmotion produces a continuous circular llrising in a conical shape to form a distributing head, and havinglpast; an-:

heavy particles.

with the water continually sup bearings 18 for a coun-.

out throu Patented Aug. 20,1912.

suitable source of power. secured thereon a bevel pinion 21 meshing with a bevel gear 22 on a vertical shaft 23 mounted in bearings 24, secured to transverse beams 25, the lower end of which shaft 23 carries a gyrating arm 26 upon which is secured a socketed part 27 in which is a ball28 mounted upon a gyrat'ing shaft 29; -Upon said shaft is carried-a feed disk 30, and to the lower end of said' shaft is secured, as shown at 31, a boss head 32, which is secured, as shown. at '33, both to a feed hopper 34 and to a. muller- 35-. The material fed into said hopper flows'through the central conduit 36' formed in the muller and on to the distributing head 11. Secured to said muller is' an annular shoe 3?. It is Said shaft 19 has in the construction of this shoe 'andof' the parts immediately connected therewith that my invention principally resides. Heretofore, owing to the location of the mercury trough relative to the other parts of the.

apparatus, great. difliculty and inconvenience have been experienced in removing from the mortar the amalgam -metal. Moreover, with s'u'ch priorfiformsof 'containing'thefprecibus gyratory mills, should the "IHOiilOilf ofgthie mill unduly slacken by raising the mullerout, of the mortar, a

mercury trough 14 is placed on the outside of the shoe, so that it is easily accessible. Furthermore, to prevent the sand clogging up the mill, the shoe is formed with an outwardly extending flange 38, which, in the gyratory mill, tends to continually deflect or depress material on to'the mercury while at the same time the or rotary wave which, continually traveling around the mill, washesthe light from the The light particles pass upward plied to the mill, while the heavy numerals are forced into the trough of mercury.

A further improvement consists in the means for securing the annular shoe of the muller, which comprises long bolts 39 which pass through the flange 38 of the shoe, the head 40 of each bolt resting against said flange, while the upper end of the bolt asses is secure or cease,-' the.'mill"'is' liable to become clogged up w1th sa'nd,'=which couldnot, in such a case, be removed except h a flange 41 of the boss heal and thereto by means of a nut i2.

In my motion of the Heretofore, the shoe has been secured to the muller by means of bolts located wholly within the mortar itself, and therefore under water, and not open to observation or easy of access. Consequently, it has not infrequently happened that a bolt or nut has become loose, and dropping between the shoe and die, has become ground up in the mill.

I By extending the ends of the bolts up to the flange of the boss head, said ends are always under observation, so that such damagecannot occur; Furthermore, the upper endof each bolt is surrounded-by a powerful coiled spring 43, which is contained in a recess 44 formed in the muller and boss head,and

- ressed at vitsllower end against an upwardly acing shoulder 45 formed on said muller and at its upper end against the nut 42 on saidbolt. vThese springs hold the shoe against the muller'tightly at all times so that the shoe does not by the unscrewing of the nuts 42 become loose from the muller. Moreover said springs afiord suflicient resilience to absorb the jar and shock taking place in the mill and prevent crystallization.

- An important featureof my invention resides in the forms of the meeting surfaces of the shoe and die.- I make both the inner upper surface a0 and the outer upper surface 51 of the die 9, and the inner lower surface-52 and the outer lower surface 53 of the shoe 37 exactly conical,- the'angle which the generatrix makes with the horizontal plane bei'ng-3O for the surfaces 50, 52, and 221} for the'surfaoes 51, 53. I find that a gyra= tory mill having a shoe and die thus formed possesses great efiiciency.

' The operation of the apparatuswill be the lighter particles escape upward with the water through one of the outlet apertures 5, 6, 7 or over the edge of the upper casing. At suitable intervals, the amalgam containing theprecious metal is drawn off.

A mill comprising anannular die, a muller, means for imparting a gyratory motion to said muller, an annular shoe, and means for securing said shoe to said muller consisting of bolts connected at the lower ends to saidshoe, parts carried by the upper ends of said bolts, the muller having upwardly facing shoulders adjacent to which said bolts pass, and .coiled springs around said bolts pressing at one end against said shoulders, and at the other end against said parts on the bolts.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

GEORGE H. BRADFORD.

Witnesses:

FRANCIS M. WRIGHT, D B. RICHARDS. 

